Current status of NPP CI in the United Kingdom

1. 1 Current status of NPP C&I in the United Kingdom T P Smyth AMEC NNC, Knutsford, Cheshire, UK

2. TWG-NPPCI, May 2007, Vienna: UK status 2 Current status of NPP C&I in the United Kingdom

3. TWG-NPPCI, May 2007, Vienna: UK status 3 Nuclear Power Plants in the UK (1)

4. TWG-NPPCI, May 2007, Vienna: UK status 4 Nuclear Power Plants in the UK (2)? Electricity sources 20% nuclear 37% gas 34% coal Need to plan for energy replacement 7 plants will close in next 11 years 14 reactors 7294 MWe 13% of electricity sources North Sea oil and gas will be limited in future 23 May 2007 Government announces 20 week consultation process Government wants to take decision this year No public money

5. TWG-NPPCI, May 2007, Vienna: UK status 5 AGR : Reactor Protection Systems (1)?

6. TWG-NPPCI, May 2007, Vienna: UK status 6 AGR : Reactor Protection Systems (2)? Obsolescence of equipment Difficulty in obtaining spares Repairs Replacement Analogue trip units Neoprene degradation New equipment Majority of protection parameters have been addressed

7. TWG-NPPCI, May 2007, Vienna: UK status 7 AGR : Reactor Protection Systems (3)? Neoprene insulation degradation Magnox Oldbury power station Degradation with age Perishing Sweating Hygroscopic Becomes conductive - resistance < 1 M? Stray currents in sensitive circuits Thermocouple amplifiers

8. TWG-NPPCI, May 2007, Vienna: UK status 8 AGR : Reactor Protection Systems (4)? Neoprene insulation degradation?

9. TWG-NPPCI, May 2007, Vienna: UK status 9 AGR : Reactor Protection Systems (5)? Neoprene insulation degradation

10. TWG-NPPCI, May 2007, Vienna: UK status 10 AGR : Reactor Protection Systems (6)? Neoprene insulation degradation Survey of all safety equipment Presence of neoprene State of neoprene Circuit function Replacement equipment at older stations Obsolescent anyway Repairs at newer stations Heysham 2 / Torness 4 years work, 2 more years to finalise all equipment

11. TWG-NPPCI, May 2007, Vienna: UK status 11 AGR : Reactor Protection Systems (7)? Neutron Flux measurement systems AGR detectors located in core at 8 locations High temperatures Detector spares Wide range detector � integral cable Manufacturing spares � re-establishing production processes Currently a batch of 10 in progress Electronic units Neoprene Complete refit Repairs at Heysham 2 / Torness

12. TWG-NPPCI, May 2007, Vienna: UK status 12 AGR : Reactor Protection Systems (8)? Diverse Guardline upgrade Hinkley B / Hunterston B / Dungeness Driven by licensing basis for nuclear power plants Large subset of Main Guardline parameters duplicated From 1995 to 2000 Heysham 2 / Torness had diverse guardlines from the outset. Hartlepool / Heysham 1 were judged to have adequate diversity in protection systems

13. TWG-NPPCI, May 2007, Vienna: UK status 13 AGR : Data Processing Systems Safety claims on equipment Some reactor control functions Some alarms Hinkley Point B New DPS installed (1999)? Dungeness B New DPS being installed Control / equipment protection functions segregated Other AGR's Stabilization of equipment Adequate spares provision / hardware support. Improved air conditioning Limited re-manufacturing (optical transceiver boards)?

14. TWG-NPPCI, May 2007, Vienna: UK status 14 AGR : Refuelling Machines (1)?

15. TWG-NPPCI, May 2007, Vienna: UK status 15 AGR : Refuelling Machines (2)?

16. TWG-NPPCI, May 2007, Vienna: UK status 16 AGR : Refuelling Machines (3)? Online refuelling Stringent safety requirements Equipment obsolescence Key focus at present Heysham 2 / Torness Replacement of Reypac controllers with Siemens S7 I/O replaced, emulates original equipment Reypac controller replacement in progress Software reverse engineered and ported Safety functions partitioned Safety standards Modern standards considered when replacing equipment

17. TWG-NPPCI, May 2007, Vienna: UK status 17 PWR : Principal C&I Systems (1)?

18. TWG-NPPCI, May 2007, Vienna: UK status 18 PWR : Principal C&I Systems (2)? Equipment Life cycle management Review of equipment status Review of spares holdings Participation of OEM (Westinghouse)? HICS Optical transceiver units obsolete New units re-engineered by Westinghouse Adequate spares manufactured

19. TWG-NPPCI, May 2007, Vienna: UK status 19 Simulators Sizewell B On site Replaced in 2003 Duplicate DPS Can be modified at the same time as the main DPS WANO recommendation AGR's Goal was to establish a simulator at each site Hartlepool - new simulator Heysham 2 / Torness Upgraded to increase fidelity WANO recommendation

20. TWG-NPPCI, May 2007, Vienna: UK status 20 Regulatory Environment (1)? Standards hierarchy NII SAPS IAEA standards IEC standards IEC 61226 PSA based assessment Target 10-7 / year Limit of reliability claims for software based systems Assume 1 demand / year 10-4/demand Require diverse protection to make up 10-3/demand

21. TWG-NPPCI, May 2007, Vienna: UK status 21 Regulatory Environment (2)? Application to Sizewell B Primary Protection System Four channels, 2 out of 4 tripping Software based Production excellence IEC 61880 Independent confidence building Extensive testing Independent code safety assessment Secondary Protection System Four channels, 2 out of 4 tripping Protection for frequent faults Laddic � magnetic amplifiers Diverse technology

22. TWG-NPPCI, May 2007, Vienna: UK status 22 Regulatory Environment (3)? New build In general, same regulatory requirements as Sizewell B Diversity requirements in reactor protection systems Possibly lower protection system targets Passively safe systems will make fewer demands Commercial Off the Shelf systems Assessment of evidence Smart Instruments Regulator considering application to nuclear facilities Assessment of evidence

23. TWG-NPPCI, May 2007, Vienna: UK status 23 Recommendations IAEA topics Estimating and extending life of I&C equipment to address ageing and obsolescence Supporting the evaluation, acceptance and licensing of digital I&C system Lessons learned from I&C project implementation and guidance for modernisation and new plant project